<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script>
		//有错误，b1是null
		var b1=document.getElementById("b1");
		b1.onclick=function(){
			alert("和照耀是皖北第二帅哥");
		}
		</script>
	</head>
	<body>
		<button type="button" id="b1">点击测试</button>
	</body>
</html>
